1. Field of the Invention
The present invention relates to a high-density recording medium such as a Blu-ray Disc-ROM (BD-ROM) and associated methods and apparatuses of recording and reproducing.
2. Description of the Related Art
Optical disks capable of storing large amounts of high-quality digital video/audio data such as DVDs (digital versatile disks) and DVD recording/reproducing apparatuses are now commercially available on the market.
Subtitle data such as caption or logo data to be superimposed on main video data of a DVD is recorded thereon as graphic data. An optical disk reproducing apparatus reproduces the subtitle graphic data and main video data of the DVD and displays the main video data and subtitle data together on the screen of an external display apparatus connected to the optical disk reproducing apparatus.
A user of such an optical disk reproducing apparatus, therefore, can view the main video data of a DVD overlaid with related subtitle data (e.g., caption or logo images) using a display apparatus connected to the optical disk reproducing apparatus.
In the mean time, the standardization of new high-density optical disks having higher storage capacity than a DVD has been progressing rapidly. The Blu-ray Disk ROM (BD-ROM) is an example of such new optical disks. An effective method for managing and reproducing subtitle data and graphic image data of the BD-ROM is not yet available.